


You're Mine

by syriala



Category: Teen Wolf (TV)
Genre: Cute, Fluff, Incest, M/M, Mates, Possessive Behavior, Uncle/Nephew Incest, tiny!derek
Language: English
Status: Completed
Published: 2018-04-04
Updated: 2018-04-04
Packaged: 2019-04-07 20:03:27
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,799
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14088606
Author URL: https://archiveofourown.org/users/syriala/pseuds/syriala
Summary: “It’s no fair,” Derek yelled and continued to smash his little fists into Peter’s stomach.“Derek, what’s going on?” Peter asked and tried to catch his hands, to at least protect Derek from hurting himself.“You’re not mine,” Derek shouted and Peter’s eyes widened, because that was as far from the truth as it could be.





	You're Mine

**Author's Note:**

  * For [lavenderlotion](https://archiveofourown.org/users/lavenderlotion/gifts).
  * Inspired by [Never Leave Me Again](https://archiveofourown.org/works/14088417) by [syriala](https://archiveofourown.org/users/syriala/pseuds/syriala). 



> This was written for Teen Wolf 'Cest Appreciation Week, day 8, Dealer's choice.
> 
> [Lavenderlotion](https://lavender-lotion.tumblr.com/) had some cute ideas about tiny!Derek from [the mates story for day 1](https://archiveofourown.org/works/14088417) and I just had to write it!

When Peter came home, he instantly realized that something was wrong with Derek.

He couldn’t see him, but he was so attuned to his heartbeat that he could hear it everywhere in the house, and it was beating way too fast, like he was upset. He smelled wrong too, like misery and anger, and Peter’s mate was never supposed to smell like that, so he immediately went looking for Derek.

Derek was in his room, angrily stabbing and hugging his plush bear in turns and Peter slowly walked into the room.

“What’s wrong, pup?” he asked, and was immediately hit with the bear.

Peter had just enough time to catch the bear before Derek was there, hitting him in the stomach over and over again.

Peter almost doubled over; Derek might be only four, but he was still a werewolf and he had a knack for hitting the squishy bits.

“It’s no fair,” Derek yelled and continued to smash his little fists into Peter’s stomach.

“Derek, what’s going on?” Peter asked and tried to catch his hands, to at least protect Derek from hurting himself.

“You’re not mine,” Derek shouted and Peter’s eyes widened, because that was as far from the truth as it could be.

“Why do you say that?” he asked and Derek renewed his efforts at hitting Peter.

“Mommy says you’re not mine,” Derek explained. “And that you won’t be. It’s no fair,” Derek yelled again before all his anger suddenly vanished and he started to cry.

“It’s no fair,” he sobbed. “I’ve been good.  I ate the green stuff and don’t hit Cora. Why are you not mine?” he asked between his sobs, tears streaming down his face and he was now clinging to Peter.

Peter felt the urge to tear something apart, preferably his sister, but he suppressed the urge for now. His mate needed him and that was infinitely more important.

“I’ve been good,” Derek cried out again and Peter crouched down to look at him.

“You have been,” he promised. “You have been so good, and you are mine. Your mommy is wrong. You’re mine,” he told him and Derek threw himself at Peter, arm slung around his neck to sob into his shoulder.

“Promise?” he asked after a few minutes where Peter just held him and soothingly stroke up and down his back.

“Promise,” Peter gave back. “You will always be mine.”

Derek pushed himself away from Peter then, but he didn’t let go, just put enough space between them so that he could look at Peter.

“Mates,” he said and flashed his eyes at Peter.

Peter had no idea where Derek had heard about mates already. Peter himself had known since the moment Talia had brought Derek home, but he hadn’t intended to say anything until Derek was at least in his teens. But since he was right and he had obviously figured it out for himself Peter nodded.

“Yes. You’re my mate, and I’m yours,” Peter gave back and flashed his eyes in turn.

It was worth to see how Derek’s face just lit up, smile so big it could barely fit on his small face.

Derek threw himself at Peter again, but this time to squeeze him as hard as he could manage. Peter pulled him close too, unwilling to let him go so soon again when he finally had his mate in his arms like he had always wanted.

They stayed like that for a little while, Derek rubbing his cheek all over Peter’s shoulder and chest, very effectively scent marking him, and Peter let out a low rumble, to show how pleased he was.

When they finally separated Derek looked way too smug for a four-year-old. Peter suspected it might be his influence.

“You’re gonna be a little pest about this, aren’t you?” he fondly asked and ruffled Derek’s hair.

Derek just beamed up at him and grabbed for his hand, clearly not intending to let go any time soon.

Peter was proven right when Talia called them for dinner and Derek got this look on his face, which Peter just knew meant nothing good.

Derek tugged Peter along by his hand, clearly on a mission now, and Peter could do nothing but follow, hoping that he could at least keep the look of utter adoration for his tiny mate off his face.

On their way down Derek told Peter all about his day, never mentioning the talk he clearly had with Talia, and Peter didn’t press him. He could imagine what had happened and he would be having words with his sister.

When they entered the kitchen Talia’s face immediately shut down when she saw that they were holding hands but she quickly plastered on a smile.

“Derek, why don’t you come here and help me with this,” she said and pointed at the salad she was preparing.

But Derek didn’t move towards her; instead he pressed closer to Peter, slinging his free arm around Peter’s leg for emphasis and said “Mine,” while staring his mother down.

Peter had to suppress a laugh, not only at Derek’s openly possessive behavior but also because of the way Talia’s face fell and went white.

Peter put his hand on Derek’s head, slowly stroking down his hair until his hand rested at Derek’s neck, showing his possessiveness just like Derek had, and smiled sweetly at his sister.

“It seems like Derek figured out that we’re mates much earlier than I intended to tell him,” he casually said. “I think you won’t be too upset, right?” Peter sweetly asked his sister.

Peter could swear that Talia’s eye was twitching but she pressed out a “Of course not,” before she quickly turned away from them.

When they all settled for dinner, Talia tried again to get Derek away from Peter, but she clearly hadn’t planned on Derek’s stubbornness.

Instead of following his mothers thinly veiled order he settled down in Peter’s lap, back pressed to Peter’s chest and slinging Peter’s arm around his middle.

Everyone was eyeing them strangely, until Derek huffed and said: “We’re mates.” Before anyone could really react to that he tipped his head up and asked Peter: “Do I have to eat the greens?”

Peter leaned down to press a kiss to his forehead, so that no one would see him laugh, and told him: “You have to eat the greens. You want to get big and strong, right?”

Derek huffed, clearly displeased, but accepted the vegetables on his plate nonetheless.

Peter quickly learned to eat around Derek, since he continued to sit on his lap for every meal. Peter wasn’t going to complain; it was a novelty having his mate this close with Derek knowing, if not completely understanding, what it meant. It was definitely worth it to see Talia getting more resigned every time it happened.

She had tried to catch Peter alone, supposedly to yell at him, but Derek didn’t let him out of his sight.

Derek had taken to sleeping in Peter’s bed, curled up small in front of him, perfectly fitting in Peter’s arms, and he stirred whenever Peter tried to slip out without him.

Peter got used to it quicker than he thought he would, and not once did he wish Derek would give him some privacy.

It became a little bit of a problem when Derek went to kindergarten, because he refused to be picked up by anyone but Peter, but he was able to work his schedule around.

Derek never really did move out of Peter’s room again, not even when he got older.

When Talia mentioned some extended travel for Peter when Derek was twelve, Derek stared her down until she finally relented.

When she suggested that Peter might need some privacy every once in a while when he was fourteen, Derek cheekily suggested that there was nothing Peter couldn’t do while he was around.

Peter choked on his drink, coughing up a lung before he promised a fuming Talia that there was nothing untoward going on at all.

They slept together, yes, but sleeping was all they did. Peter would never do anything that could cause his mate harm.

Talia was grinding her teeth so hard together, Peter was distantly worried she would break one, but it was hard to continue to pay attention to his sister when his mate curled into his side.

Derek never did learn boundaries and privacy when it came to Peter, and it was not like Peter minded.

When Derek turned sixteen he pushed for more than the usual cuddles, tried to kiss Peter whenever he caught him unawares, and he was quickly wearing Peter down until he finally relented to small kisses.

Derek tried to push that too, until Peter very clearly told him that nothing more would happen until Derek was older. They negotiated like their life depended on it, and Peter had no clue how it happened, but somehow he agreed to petting and making out when Derek was seventeen and promised him everything as soon as he turned eighteen.

Derek had never really lost the smug look on his face whenever it came to anything to do with Peter, and Peter couldn’t even say he minded.

Whenever they were in the same room they were touching, and Peter was so used to Derek by his side that he missed him desperately when they weren’t together.

Talia had gone gray long before her time, and Peter liked to think that it was all because of them. Derek never really stopped reminding her that Peter was his, casually possessiveness never leaving their interactions and Peter couldn’t even remember what it was like to not smell like Derek and mate.

When Derek’s eighteen birthday came closer and Talia asked him what he wanted to do, he absentmindedly mentioned that he would be moving out and live with Peter and wouldn’t need his mother planning anything for him.

Peter did a double take, because it wasn’t like they ever talked about that, but it didn’t really come as a surprise. Derek was the only reason he was still living in his sister’s house and he itched to have is own place. It hadn’t even occurred to him that he would move out without Derek but they also hadn’t talked about it.

Peter suspected he should be used to this by now, but he was always pleasantly surprised at how thoroughly Derek was claiming him over and over again.

The day they moved out Derek said that they finally had everything they ever wanted and Peter easily agreed with him, even though Peter had have everything he ever wanted since the day four-year-old Derek had declared him his.

But it wasn’t like he was going to complain about anything more he got.


End file.
